Disease relevance of L-leucine

• Strong aggregation and increased toxicity of polyleucine over polyglutamine stretches in mammalian cells [1].
• The results indicate that signal peptide hydrophobicity can completely override possible requirements for negatively charged residues and strong beta-turn forming potential in the mature protein and that the polyleucine-containing signal peptide may act as a generic signal sequence for the transport of non-native proteins in E. coli [2].
• The in vitro uptake of 14C-glycine, 14C-leucine and 35S-methionine by red blood cells as well as the red blood cells and plasma amino acid patterns were studied in 20 children with protein-calorie malnutrition [3].
• Suspension cultures of human KB cells infected with human adenovirus 2 were treated with 25 mu-g/ml of arabinosylcytosine starting at 2 hr to block the synthesis of viral structural proteins, and then labeled with (3H)leucine from 6 to 24 hr after infection [4].
• The incorporation of 14C-leucine into rabbit lung slices was monitored in the absence and presence of selected drugs and chemicals relevant to the perturbation of lung function and the development of lung disease [5].

Psychiatry related information on L-leucine

• Physical activity and inactivity influences on 14C-leucine incorporation in reinnervated rat gastrocnemius [6].
• Based on the data suggesting overlapping susceptibility for schizophrenia and bipolar disorder, we genotyped the polymorphic (CTG)n encoding polyleucine repeat in exon 1 of NOTCH4 in 65 pedigrees ascertained for a genetic linkage study of bipolar disorder [7].

High impact information on L-leucine

• The rate of CSP biosynthesis as measured by pulse-labeling with 14C-leucine was not altered [8].
• The processing of the neutral proteases cathepsin G and neutrophil elastase, normally synthesized in myeloid precursor cells and stored in azurophil granules, were investigated by biosynthetic labeling with 14C-leucine of the monoblastic cell line U-937 [9].
• A 12-residue-long polyleucine tail is sufficient to anchor synaptobrevin to the endoplasmic reticulum membrane [10].
• Viability of hepatocytes was documented by trypan blue exclusion (greater than 90%), time-dependent 14C-leucine incorporation into protein, and dose-related incorporation of glucose into glycogen [11].
• To define further the mechanisms of alloantiserum-mediated suppression and to utilize this suppression as a probe of the cellular events occurring during lymphocyte activation, we have examined the effects of alloantisera on 14C-leucine and 3H-uridine incorporation, earlier events after antigen stimulation [12].

Chemical compound and disease context of L-leucine

• In 29 volunteers, the basal rate of 14C-leucine incorporation into mucosal protein averaged 41.2 +/- 7.7 X 103 cpm/mg protein (mean +/- S.D.). One and 4 hours after s.c. administration of pentagastrin (6 mug/kg body weight), values were significantly increased (p less than 0.05) by 18.9 and 21.8%, respectively, with respect to the basal level [13].
• The anabolic activity of formebolone was studied in 7 patients with nephrosis or renal insufficiency by measuring the amount of 14C-leucine incorporated into plasma proteins as an index of protein synthesis [14].
• The effects of increasing extracellular concentrations of Ca2+ and Mg2+ on the uptake of 14C-thymidine, 3H-uridine and 14C-leucine by Novikoff hepatoma and normal liver cells have been studied [15].
• Hypertrophy, the predominant cellular phenomenon following chronic isoproterenol treatment, was associated with a marked elevation of 14C-leucine incorporation into the buffer soluble protein fraction and a less pronounced isotope incorporation into the sedimental sub-cellular fraction as well as continued DNA synthesis [16].

Biological context of L-leucine

• An insight into the kinetics, mechanism and optimum reaction conditions of the Julia-Colonna epoxidation has been gained using a soluble polyleucine catalyst [17].
• Cytotoxicity was assessed in in vitro 4-day cultures using 14C-leucine incorporation as an indicator of cell viability [18].
• Development of fetal thyroid function lags in the Tx mother. rRNA, total 14C-leucine incorporation, and 14C-leucine incorporation into ribosomal protein per microgram of rRNA continue to be significantly depressed in these fetal tissues and placentas of Tx rats on the 19th day of gestation [19].
• In vivo incorporation of 14C-leucine into acid insoluble material and in vitro aminoacylation of tRNAleu were studied in visual, somaesthetic and motor brain cortices [20].
• On POD 5, all patients underwent resting energy expenditure determination and a protein metabolic study using the isotope 14C-leucine to determine whole body (WB, micromol leu/kg/min) protein kinetics [21].

Anatomical context of L-leucine

• Rat embryo fibroblasts were grown in medium containing 14C-leucine and 3H-thymidine [22].
• Postmitochondrial supernatant, cytosol, and microsomes were exposed to near-ultraviolet light and assayed for incorporation of (3H)leucine [23].
• After proteolysis and chondroitanase digestion of the proteoglycan, a fraction with absorbance at 260 mn was eluted from Dowex 1 with water which stimulated the incorporation of (3H)leucine by macrophages and inhibited their migration from capillary tubes [24].
• Incorporation of (3H)leucine into three subfractions of myelin in murine myelin dysgenesis: the quaking mutant [25].
• 14C-leucine and 3H-glycerol-labeled microsomes and mitochondria were intravenously injected into a series of highly inbred rats [26].

Associations of L-leucine with other chemical compounds

• With the fibroblasts, a 50% decrease in incorporation of 14C-thymidine was observed after a 22-hr exposure to PtCl4 at a concentration of 0.007mM; higher concentrations were required to inhibit the incorporation of 14C-uridine and 14C-leucine [27].
• These results seem to indicate that 14C-leucine uptake was dependent on integrity of glycoprotein structure of synaptosomal membranes [28].
• Decreased uptake of (3H)leucine during progesterone induced maturation of Xenopus laevis oocytes [29].
• The 14C-leucine assay modified by solubilization of cells with SDS and by trichloroacetic acid precipitation showed increased recovery of labeled protein and, thus, lower cytotoxicity, about 50%, at 4 h [30].
• Little or no incorporation of 14C-leucine into polypeptides was observed, inspite of tha fact that considerable number of ribosomes and nascent RNA chains were found attached to the isolated nucleoids [31].

Gene context of L-leucine

• No incorporation of 14C-leucine to the position of P400 protein was found in the nervous and pcd mutant mice where no Purkinje cells and no P400 protein are present [32].
• 14C-leucine incorporation, and TGF-alpha, beta-FGF, and EGF-receptor levels were assessed in gastric and duodenal mucosa in 20 patients with HP-associated gastritis and repeated after treatment of the gastritis, with or without eradication of the organism [33].
• Synthesis of alpha 1-antitrypsin by monocytes, granulocytes and HL-60 cells was demonstrated by 14C-leucine incorporation [34].
• Production and release of lymphotoxin (LT) was studied by metabolic labeling of human B- and T-cell lines with 14C-leucine and 35S-methionine [35].
• Gastrin (10 micrograms/ml) enhanced 14C-leucine uptake in cultured tissue of stomach and colon carcinomas and content of 14C-labelled protein in the medium was increased [36].

Analytical, diagnostic and therapeutic context of L-leucine

• To this aim, we have measured kidney protein synthesis and degradation in postabsorptive humans using the arterio-venous catheterization technique combined with 14C-leucine, 15N-leucine, and 3H-phenylalanine tracer infusions [37].
• To examine this question, we performed paired euglycemic insulin clamp studies in combination with 14C-leucine and indirect calorimetry [38].
• Serum subfractions obtained from uremic patients inhibited apo A-I synthesis and secretion by Hep-G2 cells in a dose-dependent manner as measured by (3H)leucine incorporation into apo A-I, immunoprecipitation, and ELISA [39].
• Protein turnover in striated muscle as visualized by radioautography after (3H)leucine administration [40].
• After immunoprecipitation of 14C-leucine-labelled proteins from a JB1 cell lysate by MRC TU/J1, 5 bands in the molecular weight range 43,000-49,000 daltons were visualized on 10% SDS-PAGE gels [41].

References